Air-conditioning device of automatic ventilation type

ABSTRACT

An air-conditioning device embodying means for detecting the level of contamination of air in a room, means for heating and/or cooling, an air intake and exhaust and a control device for automatically operating the air intake and exhaust to provide for either recirculation of air within the room when the contamination level is below a selected value or for exchanging air in the room when the contamination level exceeds a predetermined value.

United States Patent Watanabe Y [451 Jan. 18,1972

[54] AIR-CONDITIONING DEVICE OF AUTOMATIC VENTILATION TYPE [72] Inventor: Koichi Watanabe, Akashi, Japan [73] Assignee: New Cosmos Electric Co., Ltd., Osaka,

Japan [22] Filed: June 1, 1970 [21] App1.No.: 42,342

[30] Foreign Application Priority Data June 5, 1969 Japan ..44/44l74 [52] US. Cl ..l65/ll, 165/26 [51] Int. Cl ..F28f 13/00 [58] Field of Search ..236/49, 98/49, 50, 23/255, 165/1 l, 70

[56] References Cited UNITED STATES PATENTS 1,603,107 10/1926 Hatch ..236/38 2,339,987 1/1944 Evans ...98/49 2,726,594 12/1955 Cooper ..98/49 2,533,339 12/1950 Willenborg ..98/49 UX Primary ExaminerEdward J. Michael Attorney-Eugene E. Geoffrey, Jr.

[5 7] ABSTRACT An air-conditioning device embodying means for detecting the level of contamination of air in a room, means for heating and/or cooling, an air intake and exhaust and a control device for automatically operating the air intake and exhaust to provide for either recirculation of air within the room when the contamination level is below a selected value or for exchanging air in the room when the contamination level exceeds a predetermined value.

5 Claims. 8 Drawinz Figures AIR-CONDITIONING DEVICE F AUTOMATIC VENTILATION TYPE This invention relates to the ventilation of rooms and buildings and more specifically to a novel and improved system for ventilating rooms or buildings while they are being heated or cooled. In many cases the air in rooms and particularly closed rooms which are heated or cooled become contaminated by reason of the burning of fuel or the like and it therefore become necessary to ventilate the room manually. In instances where heated or cooled air is cleaned or filtered while being continuously fed into the room or other space being ventilated, the efficiency of the heating or cooling process is very low because heated or cooled air is discharged from the room and is not merely circulated.

One object of the invention resides in the utilization of a novel and improved system for room ventilation utilizing a gas-detecting element for measuring air contamination so that heated or cooled air will not be arbitrarily discharged if the air is uncontaminated. With this invention the ventilation or exchange of air within a room is effected only when contamination has reached a predetermined level as determined by the gas-detecting element in which case the ventilating means is automatically operated. Under these conditions, the thermal loss resulting from the discharge of heated or cooled air when the air is not contaminated is prevented. As a result, a clean healthy atmosphere is maintained as ventilation is only performed under conditions wherein the contamination exceeds a selected level.

The gas-detecting element utilized with this invention includes a pair of electrodes, at least one of which is heated and a metal oxide semiconductor which encloses both electrodes. The metal oxide semiconductor may be formed for example of SnO ZnO, Nb O TiO or Fe O The heater electrode heats the metal oxide semiconductor to a temperature in the range of 50 to 300 C., and an alternating current voltage is applied in series with a voltage divider across the electrodes. A voltage obtained from the voltage dividing means is fed to the gate of a thyristor which is connected in series with a relay and a source of energy. When the air in the room reaches a predetermined contamination level wherein it contains reductive gas such as carbon monoxide, fuel gas, or other gases resulting from imperfect combustion, the current' flowing through the semiconductor will increase and apply avoltage to the gate which will trigger the thyristor. The thyristor will then conduct and operate the relay which in turn will energize ventilating appa'ratus. When the contamination level of the air in the room is reduced below the selected level, the thyristor will be automatically cut off and the relay will open to terminate continued ventilation.

The above and other objects of the invention will become more apparent from the following description and accompanying drawings forming part of this application.

In the drawings:

FIG. 1 is a diagrammatic perspective view of a gas-detecting element used with this invention;

FIG. 2 is a circuit diagram of one embodiment of apparatus for ventilation and circulation'of air in a room or other space;

FIGS. 3 and 4 are diagrammatic front and plan views of a room showing the arrangement of heating and cooling devices, the ventilating fan and the control device in accordance with the invention;

FIG. 5 is a diagrammatic view of one example of a heating and cooling device for ventilating a room in accordance with the invention and wherein the device has been actuated to effect room ventilation,

FIG. 6 is a view similar to FIG, 5 and illustrates the operation of the device to recirculate air within the room;

FIG. 7 is a diagrammatic view of an exhaust fan utilized with the invention with the louvers open for the discharge of air; and

FIG. 8 is a view similar to FIG. 7 showing the louvers in the closed position.

The gas-detecting element used in accordance with the invention is illustrated in FIG. I and includes a pair of coils 1 and 2 formed of a relatively nonoxidizable metal wire such as platinum, palladium or platinum-iridium alloy. The coils are secured in grooves 4 and 5 formed on opposite surfaces of a block 3 which block is made of a heatproof electrical insulating inorganic material such as A SiO,, or BeO. The coils are fixed in position by a high-melting point glassy adhesive which may consist of M 0, dissolved with one or more of the following materials K 0, CaF Al 0 Ba O,, and SiO,. It will be observed that only a portion of each of the coils 1 and 2 will be embedded in the adhesive and the remaining portion of each coil is exposed. The block 3 and the coils l and 2 are enclosed by a metal oxide semiconductor material 8 which is sensitive to reductive gases at high temperatures. Conductors 9, 10, 11 and 12 forming part of the coils l and 2 extend from opposite surfaces of the semiconductor material.

Examples of metal oxide semiconductor materials are SnO ZnO, Nb O Ta,o,, TiO and Fe O When these substances are heated to a temperature in the range of 50 to 300 C. and come in contact with reductive gases such as carbon monoxide, fuel gas, liquid fuel vapor or organic solvent vapors, oxygen ions are removed from the semiconductor causing oxidation of the gas and producing a cation, and anion imbalance which changes the resistance of the semiconductor.

The detector is formed in the following manner. The coils l and 2 are supported in a predetermined spaced relationship by securing the conductors 9, 10, 11 and 12 to four supporting rods l3, l4, l5, and 16 which are carried by a stern made of an electrical insulating material such as plastic or the like. The insulating block 3 having grooves-4 and 5 therein, the latter being coated with a high-melting point adhesive, is placed between the coils 1 and 2 so that portions of the coils are embedded in the adhesive. A current is then fed to the supporting rods l3, l4, and 15, 16 to heat the coils to melt the adhesive and fix the coils in the grooves. The coils l and 2 and the block 3 are then enclosed within a norisintered gas sensitive oxide. The coils are again heated to sinter the oxide and thereby complete I the detector. Inasmuch as the current passed through the coils at the time of actual use is substantially lower in value than the current used in the formation of the detector, neither the adhesive nor the oxide will be melted during actual use.

FIG. 2 is a circuit diagram illustrating a control circuit for cooling, heating and ventilating, in accordance with the invention. The numeral 20 denotes the detector described in connection with FIG. 1. The power supply comprises a transformer 21 having a primary 22 connected through a fuse 23 to a plug 24 for applying either I ID or 220 v. AC to the transformer. The transformer is further provided with a secondary winding 25 for producing approximately 1.5 v. and a second secondary winding 26 for producing approximately 10 v. A coil 27 of the detector 20 which would correspond to the coil 1 of FIG. I is connected to the secondary winding 25 of the transformer. The other coil 28 has its ends connected together and serves as an electrode. The detector 20 is connected in series with resistors 29 and 30 and across the primary winding 22. The resistor 30 is a voltage divider having a movable contactor 34. A relay coil 31 and a thyristor 32 are connected in series across the secondary winding 26 and the gate electrode 33 is connected to the voltage divider arm 34. The cathode 35 of the thyristor is connected to one side of the voltage divider 30 in order to provide a control voltage. A capacitor 36' is connected across the relay in order to remove the ripple component of the AC current through the relay coil. The relay which includes coil 31 further includes contact points 36 through 39 with the contact points 36, 38, and 39 closed when the coil is energized and the contact points 37 being opened when the coil is energized. Referring now to FIGS. 3 and 4, the numeral 40 denotes a room to be heated or cooled and the control device as illustrated in FIG. 2 may be positioned at any suitable place within the room. and is represented in these figures by the block 42 which is attached to the ceiling 41. A heating and cooling device 44 is installed on the wall 43 while an air-exhausting device 46 is installed on the wall 45. The

heating and cooling device 44 is shown in FIGS. 5 and 6 and includes louvers 51 and 52 which may be opened and closed and a louver 53 which is fixed in the opened position as illustrated. The louver 51 is in the outside wall 43 and when open permits fresh air to be brought into the room. The louver 52 is on the top wall of the device 44 and permits recirculation of the air within the room. The louvers 51 and 52 are operated by springs 54 and 55 and electrically actuated devices 56 and 57 such as solenoids or the like. The springs move the louvers to the closed positions while the solenoids 56 and 57 function to open the louvers when energized. The block 58 represents a source for the supply of air and a cooling or heating medium such as a heat pump or the like. The source 58 is connected to a heat exchanger 59 positioned above the bottom louver 53. A motor driven fan 60 is positioned above the heat exchanger 59 and a temperature detecting element 61 connected with the source 58 is positioned above the fan and may function to control the temperature of the air whether heated or cooled in the room.

The air exhausting means 46 is illustrated in FIGS. 7 and 8 and comprise a louver 62 in the outside wall 45 and a motor driven fan 63. The louver 62 is operated by a spring 64 for closing the louver and an electrically operated device 65 for opening the louver.

The louver operating device 56 and 57 of FIGS. 5 and 6, the device 65 of FIGS. 7 and 8 are operated and the fan 63 are operated by the relay contacts 36 through 39 of FIG. 2. Power is supplied by a plug 66 adapted to be connected to a source of alternating current such as l or 220 v. In the operation of the apparatus described above, the heat pump 58 and the fan 60 are controlled by the temperature controlling device 61 and the lower louver 53 is open at all times. If the air in the room 49 is uncontaminated, the thyristor 32 will not operate because the current passing through the element is small. Under these conditions the relay coil 31 will be deenergized and the relay contacts 36 through 39 will be in positions as shown in FIG. 2. Thus the louver operating device 56 will be deenergized and the louver will be in the closed position. The louver operating device 57 will be energized to open the louver 52. At the same time the device 65 for operating the louver 62 will be deenergized so that the louver will be in the closed position and the fan 63 will not be operated. Under these conditions as shown in FIG. 6, the air within the room will enter the device 44 through the louver 52, pass through the heat exchanger 59 and be discharged through the louver 53 into the room. In this way, the air in the room will either be heated or cooled as desired.

Should the air in the room 40 become contaminated by carbon monoxide, fuel gas, or products of imperfect combustion and such contamination reaches a predetermined level, the resistance of the detector 20 will decrease and thereby increase 7 the voltage applied to the gate 33 of the thyristor to a magnitude causing the thyristor to fire. This will energize the relay coil causing contacts 36, 38, and 39 to close and contacts 37 to open. As a result, the louver operating device 57 will be deenergized causing the louver 52 to close while the louver actuating devices 56 and 65 will be energized to open the associated louvers. At the same time the exhaust fan 63 will also be energized. Under these conditions fresh air will be drawn in from the outside as illustrated in FIG. 5 and will pass downwardly through the heat exchanger 59 and into the room. At the same time contaminated air is discharged through the fan 63 in the open louver 62 as shown in FIG. 7.

When the level of contamination of air decreases below a predetermined level, the resistance of the element 20 will increase reducing the voltage applied to the gate 33 of the thyristor causing the thyristor to open and deenergize the relay coil 31 and cause the associated contacts to return to the position shown in FIG. 2. Under these conditions the room air will be recirculated through the device 44 as previously described.

With the invention as described above, the air in a room can alwa s be maintained in an uncontaminated clean condition and t e operating costs of the system IS materially below those of a system wherein the heated or cooled air in the room is continuously replaced with fresh air at all times.

While the invention is particularly useful with heating and cooling apparatus as shown in FIGS. 5 and 6, it is equally useful in instances where auxiliary heaters or coolers such as stoves, air conditioners, or the like are used in combination with the device 44.

While only certain embodiments of the invention have been illustrated and described, it is apparent that alterations, modifications and changes may be made without departing from the true scope and spirit thereof as defined by the appended claims.

What is claimed is:

1. A space air-conditioning system for rooms, buildings and the like comprising an enclosure including air heating and cooling means, gas-detecting means and temperature control means, said enclosure including a fresh air inlet and shutter controlling said inlet, a room air inlet and shutter controlling the last said inlet and a room air outlet, individual means for operating said shutters, room air exhausting means, a fan within said enclosure for delivering air from said inlets to said outlet, means connecting said temperature control means with said heating and cooling means to control the temperature of the air discharged from said outlet, said gas-detecting means including a gas sensing element comprising a metal oxide semiconductor which changes its electroconductivity upon the absorption of gas and producing an output in response thereto, and a control device interconnecting said gas-detecting means with said shutter operating means and said room air exhausting means whereby the sensing of a gas of a predetermined concentration by said gas-detecting means will effect closure of the shutter associated with said room air inlet, open the shutter associated with said fresh air inlet and operate said room air exhausting means and when the concentration of gas is reduced below a predetermined level said detecting means will close said fresh air inlet, open said room air inlet and terminate operation of said room air exhausting means.

2. Apparatus according to claim I wherein said air temperature controlling means is disposed within said enclosure.

3. Apparatus according to claim 1 wherein said detector comprises a semiconductor body having a resistance variable in response to the presence of a reductive gas, a pair of electrodes in contact with said body and means for heating said body.

4. Apparatus according to claim 3 wherein said semiconductor body comprises a metal oxide selected from the group consisting of SnO ZnO, Nb O Ta O TiO and Fe O 5. Apparatus according to claim 1 wherein said control means includes a relay having a coil and a plurality of sets of contacts for controlling the opening and closing means for said shutters and the room air exhausting means, a thyristor having a control gate for energizing said relay, circuit means including said detector for producing a predetermined voltage change when contamination of the room air reaches a selected level and means for applying said predetermined voltage to said gate to cause the thyristor to conduct and operate said relay.

l i i i 

1. A space air-conditioning system for rooms, buildings and the like comprising an enclosure including air heating and cooling means, gas-detecting means and temperature control means, said enclosure including a fresh air inlet and shutter controlling said inlet, a room air inlet and shutter controlling the last said inlet and a room air outlet, individual means for operating said shutters, room air exhausting means, a fan within said enclosure for delivering air from said inlets to said outlet, means connecting said temperature control means with said heating and cooling means to control the temperature of the air discharged from said outlet, said gas-detecting means including a gas sensing element comprising a metal oxide semiconductor which changes its electroconductivity upon the absorption of gas and producing an output in response thereto, and a control device interconnecting said gas-detecting means with said shutter operating means and said room air exhausting means whereby the sensing of a gas of a predetermined concentration by said gasdetecting means will effect closure of the shutter associated with said room air inlet, open the shutter associated with said fresh air inlet and operatE said room air exhausting means and when the concentration of gas is reduced below a predetermined level said detecting means will close said fresh air inlet, open said room air inlet and terminate operation of said room air exhausting means.
 2. Apparatus according to claim 1 wherein said air temperature controlling means is disposed within said enclosure.
 3. Apparatus according to claim 1 wherein said detector comprises a semiconductor body having a resistance variable in response to the presence of a reductive gas, a pair of electrodes in contact with said body and means for heating said body.
 4. Apparatus according to claim 3 wherein said semiconductor body comprises a metal oxide selected from the group consisting of SnO2, ZnO, Nb2O5, Ta2O5, TiO2, and Fe2O3.
 5. Apparatus according to claim 1 wherein said control means includes a relay having a coil and a plurality of sets of contacts for controlling the opening and closing means for said shutters and the room air exhausting means, a thyristor having a control gate for energizing said relay, circuit means including said detector for producing a predetermined voltage change when contamination of the room air reaches a selected level and means for applying said predetermined voltage to said gate to cause the thyristor to conduct and operate said relay. 